Nokea
The most common second messengers for peptide hormones are ______ and _____.
- A. peptide hormones and calcium.
- B. calcium and glucose.
- C. cAMP and calcium.
- D. cAMP and sodium.
Correct Answer: C
Rationale: The correct answer is C: cAMP and calcium. Peptide hormones bind to their receptors on the cell surface, activating G-proteins which then trigger the production of cAMP as a second messenger. cAMP then further activates protein kinases to initiate various cellular responses. Calcium is also a common second messenger in peptide hormone signaling pathways, regulating processes like muscle contraction and gene expression. Choice A is incorrect because peptide hormones themselves are not second messengers. Choice B is incorrect as glucose is not a common second messenger for peptide hormones. Choice D is incorrect as sodium is not typically involved in peptide hormone signaling pathways.
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Which one of the following properties makes labetalol different from nearly all the other β-blockers on the market?
- A. Also blocks alpha-adrenergic receptors
- B. Causes strong atropine-like side effects, has same side effects as atropine
- C. Only blocks β1 receptors
- D. Safe for asthmatics because it lacks β2 blocking activity
Correct Answer: A
Rationale: The correct answer is A because labetalol is unique among most β-blockers as it also blocks alpha-adrenergic receptors. This dual action results in vasodilation and reduced blood pressure. Choice B is incorrect as labetalol does not cause atropine-like side effects. Choice C is incorrect as labetalol blocks both β1 and β2 receptors. Choice D is also incorrect as labetalol does have some β2 blocking activity, making it not entirely safe for asthmatics.
Which gland is considered the most influential endocrine gland?
- A. Pineal gland
- B. Pituitary gland
- C. Thyroid gland
- D. Adrenal gland
Correct Answer: B
Rationale: The correct answer is B: Pituitary gland. The pituitary gland is considered the most influential endocrine gland because it controls the functions of other endocrine glands by secreting various hormones that regulate growth, reproduction, metabolism, and other bodily functions. It is often referred to as the "master gland" due to its crucial role in maintaining hormonal balance and homeostasis in the body.
Rationale:
A: Pineal gland - The pineal gland primarily regulates the sleep-wake cycle through the secretion of melatonin and is not as influential in overall endocrine function as the pituitary gland.
C: Thyroid gland - The thyroid gland regulates metabolism through the production of thyroid hormones, but it does not have the same level of control over other endocrine glands as the pituitary gland.
D: Adrenal gland - The adrenal gland produces hormones like cortisol and adrenaline, which are important for stress response and metabolism, but it does not have the same regulatory influence over other
Concerning Alpha blockers, which of the following is CORRECT:
- A. Phentolamine is a selective Alpha1 blocker
- B. Alpha2 blockers decrease noradrenaline release
- C. Prazosin can block Alpha1 receptor only
- D. They decrease both BP and HR
Correct Answer: C
Rationale: Rationale:
C: Prazosin can block Alpha1 receptor only.
- Prazosin is a selective Alpha1 blocker, mainly used for hypertension.
- By blocking Alpha1 receptors, it reduces vasoconstriction and lowers blood pressure.
- Prazosin does not affect Alpha2 receptors, distinguishing it from non-selective Alpha blockers.
- Correct as it accurately describes Prazosin's mechanism of action.
Incorrect:
A: Phentolamine is a non-selective Alpha blocker, affecting both Alpha1 and Alpha2 receptors.
B: Alpha2 blockers increase noradrenaline release by inhibiting the negative feedback control.
D: Alpha blockers typically decrease blood pressure, but can increase heart rate due to vasodilation.
Name the gland that is located at the base of the throat, just inferior to the laryngeal prominence (Adam's apple).
- A. Pituitary.
- B. Pineal gland.
- C. Hypothalamus.
- D. Thyroid.
Correct Answer: D
Rationale: The correct answer is D: Thyroid. The thyroid gland is located at the base of the throat, just below the Adam's apple. It is responsible for producing thyroid hormones that regulate metabolism and various bodily functions. The pituitary gland (A) is located in the brain, the pineal gland (B) is located in the brain as well, and the hypothalamus (C) is also in the brain. These glands play crucial roles in hormone regulation, but they are not located at the base of the throat like the thyroid gland.
Which of the following is not a change that may be caused by hormonal stimulus?
- A. a change in membrane potential
- B. the stimulation of a genetic event resulting in protein synthesis
- C. an increase in enzymatic activity
- D. direct control of the nervous system
Correct Answer: D
Rationale: The correct answer is D: direct control of the nervous system. Hormonal stimuli typically target specific cells or tissues to elicit a response, such as changes in membrane potential, genetic events leading to protein synthesis, or an increase in enzymatic activity. Hormones do not directly control the nervous system, as the nervous system operates independently and responds to its own set of stimuli. Therefore, D is the correct answer as it does not align with the typical effects of hormonal stimulation. Choices A, B, and C are incorrect as they are all changes that can be caused by hormonal stimuli.